Add news API integration and related configurations

- Update .env.example to include NEWS_API_KEY configuration
- Add newsapi-python dependency in pyproject.toml
- Implement NewsAPI class for fetching news articles
- Create Article model for structured news data
- Add tests for NewsAPI functionality in test_news_api.py
- Update pytest configuration to include news marker

tests/api/test_news_api.py

@@ -0,0 +1,19 @@
+from app.news import NewsAPI
+
+class TestNewsAPI:
+
+    def test_news_api_initialization(self):
+        news_api = NewsAPI()
+        assert news_api.client is not None
+
+    def test_news_api_get_top_headlines(self):
+        news_api = NewsAPI()
+        articles = news_api.get_top_headlines(query="crypto", total=2)
+        assert isinstance(articles, list)
+        assert len(articles) == 2
+        for article in articles:
+            assert hasattr(article, 'source')
+            assert hasattr(article, 'time')
+            assert hasattr(article, 'title')
+            assert hasattr(article, 'description')
+